Central Asia, largely peaceful since a bloody uprising in Uzbekistan in 2005, has become more volatile in recent weeks as fighting intensified in neighboring areas of Afghanistan and Pakistan.

Security analysts say the surge of U.S. troops in Afghanistan, and Pakistan's offensive against militants in tribal areas, may have forced some Taliban fighters of Central Asian origin to trickle back into the former Soviet region.

Kyrgyzstan's 24.kg news agency reported that the state security agency had arrested 18 suspected militants who used to fight alongside the Taliban in Afghanistan and were now involved in sending supplies to Afghanistan and other logistical matters.

It said in a report late on July 17 that the group included citizens of Kyrgyzstan, Uzbekistan, and Kazakhstan.

Central Asia, a vast strategic region between Russia, China, Afghanistan and Iran, is also a key transit route for supplies headed for U.S. and NATO troops in Afghanistan.

Governments in Central Asia have blamed the latest attacks on the Islamic Movement of Uzbekistan, a group whose militants have long fought alongside the Taliban in Afghanistan.

In the latest in a series of attacks on security forces across the region, Tajik forces killed five gunmen in a shootout near Tajikistan's border with Afghanistan.

In another clash, Kyrgyz security forces killed three men they described as Islamist extremists in a gun battle in the Ferghana valley, Central Asia's most densely populated area.